Trailer brakes fixed, need help with interior lights

[acade]

alright guys, I picked up my 16 ft enclosed trailer today...nice trailer. My truck just had the 4 pin connector, and I installed a 7 pin. Also, I installed a Reese POD brake controller. The problem: the trailer has a utility light inside, however, it only works when I turn the truck lights on. ??? Whats going on there? Also, with my new brake controller, I used the Ford pigtail adaptor, and double checked that I wired into the brake controller right. However, I can't tell if the brakes are working. Has anyone used the Reese POD or had any experience with it? Thanks guys...hopefully I can get this figured out soon, I'm gonna be putting alot of miles on it next week.

Originally Posted by Added in edit by Believer45

Acade started another thread for just the interior lights but there is a LOT of information already here. Please help him out with interior lights, he got the rest of it fixed.

Originally Posted by acade posted this in another thread that I closed to avoid confusion

I just picked up my new 14 ft enclosed trailer yesterday and love it. However, the interior light only works when the truck lights are on. If the truck is running and the lights are OFF, the interior light still doesn't work. So, i'm not sure if the interior light is just spliced into the running lights, or if there is something I have done wrong. I checked my trailer plug wiring on the truck twice, and all the wires are correct. I checked the fuses for something like 'auxiliary trailer power' but didn't find anything. What am I missing? Or is the trailer just wired to turn the interior light on when the truck lights are on? This could get annoying after a while.

[Ruff]

There is no power to the trailer plug with the key off. Your interior light is working normally.

If you hold the brake lever on the controller, from a stop you should see/feel the trailer brakes engaging...

Ruff

[acade]

Originally Posted by Ruff

There is no power to the trailer plug with the key off. Your interior light is working normally.

I turned the key to accessory, and nothing, but when the key is off, and I turn on the truck lights, the interior light will work. I would think the interior light would work even with truck off, lights off, and key off...isn't that the point?

Originally Posted by Ruff

If you hold the brake lever on the controller, from a stop you should see/feel the trailer brakes engaging...
Ruff

The brake controller I use its supposed to light up green when the trailer is plugged in, and turn red when brakes are applied. The green light never comes on, but when I press the brakes, the red light comes on. ???? So obviously the unit is getting power, but is it braking the trailer?

I have a feeling this may have something to do with the interior light problem...because the interior light runs off the battery, and the brakes run off the battery......so, still not sure.

[wittmeba]

It sounds like the lighting inside the trailer is connected to the running lights of the truck (Pin 3). Do your inside trailer lights work when not connected to the truck?

You may have a case where you want to run the lights on Pin 7 (usually not used) and connect the battery power (Pin 4) on from the truck to Pin 7 on the truck connector. Then when plugged in, you will have power from the truck. If you do this on the trailer connector, you may drain the battery one the trailer when not connected to the truck.

Here is a diagram of basic trailer lighting wiring.



You need to be careful that if you use the trailer battery (required for emergency braking in the event of disconnect) and forget to turn the lights off and they drain the battery, until they recharge you wont have any emergency power for braking.

Here is a diagram of the proper connection for 6/7 pin connectors for verification.




When testing a brake controller be sure you have it set to max. Otherwise, you may not be providing enough voltage to know if it is working at all.

[SmokeyWren]

Originally Posted by acade

I would think the interior light would work even with truck off, lights off, and key off...isn't that the point?

If the trailer has its own battery for other than hitch disconnect, then you can turn on the interior lights any time. My RV trailer is wired that way. Big deep-discharge marine battery that will fire the lights (and furnace fan and reefer) when not plugged into the truck.

But my cargo trailer doesn't have that battery. It has only the small battery on the hitch that will lock the trailer brakes if the hitch disconnect is unplugged.

You need to determine which of the 7 wires in the 7-pin plug the interior light switch is connected to.

Here are the wire colors in a standard 7-pin RV plug:

1 white = common ground
2 blue = electric brake
3 green = tail/running lights
4 black = battery charge (+)
5 red = left turn/stop
6 brown = right turn/stop
7 yellow = auxiliary/back up

But some trucks are wired differently, so you should check yours. Use a test light on the trailer connection plug on the truck.

With no lights or turn signals turned on and with the tranny in park or neutral, only the black wire should have power. And even it may not have power if the key is off. But test it and see if it's hot with the key off. If it's not hot with he key off, then the key will have to be on before the black wire could work to turn on the lights. But if the black wire is hot with the key off, and the interior lights are connected to that wire, then the trailer lights should work any time the trailer was plugged into the truck.

Turn on the parking lights and both the green wire and the black wire should now have power, but none of the others.

It sounds like your interior lights are wired into the wire from the truck normally used for tail/running lights. So the interior light would work only when the truck lights were turned on. And maybe the key would have to be on too.

The black wire is normally used to charge the battery in the trailer. If that wire is a hot-all-the time wire, and your interior lights are wired to that wire, then the interior lights would work any time the trailer was plugged into the truck.

If your trailer has the small battery on the hitch but not a big marine battery for the lights and accessories in the trailer, then you could change the wiring for the interior lights to connect to the battery on the hitch. That would make the interior lights work any time you turned on the switch, even when not plugged into the truck - but will also run down the small battery if you leave those light(s) on very long without the engine running to keep the battery charged.

[acade]

so, the battery for the brake is recharged when the truck is running? if that is so, then I will wire the interior light to that battery, I only turn it on when it is dark and am loading my bike.....which is not very often

[wittmeba]

Originally Posted by acade

so, the battery for the brake is recharged when the truck is running?

That is correct. It is charged by your truck.

About your brakes. It is important to remember the output is a variable based on the braking demand. When the manual operator is used there should be an output based on the value that you preset for your output. It will NOT output the max unless you adjust to the max and then use the manual operator to the max.

Troubleshooting - try to first determine if it is the tow vehicle/brake controller or the trailer.

[acade]

yeah, I definitely think the interior light was just spliced into the running lights, cuz I just got done trying every combination of lights on, off, accessory on, etc. So, I pulled the battery out of the trailer, and all I can say is wow...the wiring in that little box that holds the battery is crazy...the battery has a ground to it, and a blue wire to the positive, which then has a black wire spliced into it. I am assuming this is the 12v wire that will recharge the battery when truck is running? And the blue wire is for the electric brakes, right? So, I guess just hook up the interior light to the positive...will I need to run a ground wire also?

thanks for all the help fellas, I am new to the trailer pullin' club

[SmokeyWren]

Originally Posted by acade

So, I guess just hook up the interior light to the positive...will I need to run a ground wire also?

If the interior lights worked before under the combo of key on/lights on, then the ground wire is already hooked up right. All you need is a source for positive (12-volt hot) that will be there when you want to turn on the lights.

[acade]

I was doing some searching around on the forum, and someone had the same problem...there 12v interior light would only come on when the truck lights are on...so maybe its supposed to be like this...also they said that ford doesn't have a 12v hot wire all the time...?

[acade]

alright fellas, just stopped by advanced and picked up some fuses...I looked in the manual and there are several fuses for trailer brake controller and trailer battery...I didn't have those fuses in my power distribution box...some now my brake controller and trailer brakes are good to go...but still....that interior light...only on when running lights on...am I missing a fuse for that too? I looked through several times and nothing jumped out at me for fuses for auxiliary trailer power....any suggestions?

[Believer45]

I have seen interior lights wired this way often when folks install the lights after the trailer was built. I do not know if any manufacturers do this or not. I have seen straight trucks with box bodies wired so the box interior lights only work with the truck parking lights on but they are rentals and this may be to prevent folks from killing batteries by leaving interior lights on.

Dave / Believer45

[acade]

alright, I checked the fuse box under the hood, and the 'trailer back up lamp relay' and 'trailer battery charge relay' are not there, so I'll go pick a couple up at advanced and see what that'll do...this is starting to get irritating

[Believer45]

Too bad you can't check with dealership (if new) or the manufacturer. Darn weekends!!

[acade]

well crap, put in those relays, and still nothing (without the running lights on)....